Plastic compositions containing dialkyl monochlorophosphonate esters



United Sees atent PLASTIC COMPUSITIONS CONTAINING DIALKYL MQNOCHLORGPHQSPHONATE ESTERS Arthur Dock Fen Toy, Park Forest, and Kenneth H. Rattenbury, South Chicago Heights, Ill., assignors to Victor Chemical Works, a corporation of Illinois No Drawing. Griginal application August 23, 1954, Serial No. 458,004. Divided and this application November 21, 1955, Serial No. 548,276

6 Claims. (Cl. 106-177) This invention relates to plasticized resin and plastic compositions containing dialkyl monochlorophosphonate esters containing from 3 to 10 carbon atoms in the hydrocarbon radicals.

This application is a division of applicants copending application Serial No. 458,004, filed August 23, 1954.

The plasticizers commonly available normally are of little or no value at low temperatures. There is an increasing demand for civilian and military purposes for such low temperature plasticizers, particularly for use in artificial leathers for garments, seat covers for trucks, and other items which must remain flexible at low temperatures.

The plasticizing agents of this application likewise are of particular value in their ability to impart flame-resistant characteristics to the plasticized resin or plastic products. This characteristic varies somewhat with the type of resin or plastic employed. For example, excellent flame resistance is obtained with vinylite, cellulose acetate and ethyl cellulose, whereas with nitrocellulose very little increase in flame resistance is obtained though an excellent low temperature plasticization is effected.

In the preparation of the new plasticizing compounds, it is first necessary to prepare, by known means, the monochloromethanephosphonic dichloride, and then react this material with the desired alcohol under suitable conditions to produce the dialkyl ester of the monochloromethanephosphonic acid. For example, the preferred ester, di(2-ethy]hexyl) monochloromethanephosphonate was prepared by reacting monochloromethanephosphonic dichloride and 2-ethyl hexanol in the following manner:

In a three-necked liter flask equipped with thermometer to was reduced to 4 mm. and the heating continued for one and one-half hours to substantially remove all of the liberated hydrogen chloride. The solution was then transferred to a distillation unit and the excess Z-ethyl hexanol distilled oii at 3 mm. pressure and 5363 C. The crude product was washed with 300 ml. of 5% NaI-ICO solution and the organic layer separated and distilled at 150 to 163 C. at 1 mm. pressure yielding 189.4 grams (93.5% yield) of di(2-ethylhexyl) monochloromethanephospho nate. The ester product had an index of refraction N =L4505 and an acidity equal to 0.35 ml. of 0.1 N

5 ride acceptor, as follows:

In a three-necked 5 liter flask was placed 315.0 grams of n-propanol (5.0 moles plus 5% excess), 530.2 grams of triethylamine (5.0 moles plus 5% excess) and 2 liters of benzene. The solution was cooled to 0.0 C. and

419 grams (2.5 moles) of monochloromethanephosphonic dichloride added dropwise with stirring at 05 C. over a 2 hour and 50 minute period. The slurry was stirred for one hour at O-5 C. and allowed to stand over night. The slurry was then filtered to remove the amine hydrochloride and the cake washed with 900 ml. of benzene.

The filtrate was placed in a 5 liter distillation unit and the volatiles stripped off at C. and 1 mm. pressure. The liquid product was then distilled at a vapor temperature of 78-90 C. at 1 mm. pressure yielding 435.0 grams 0 (81.4% yield of di-n-propyl monochloromethanephosphonate having an index of refraction N =l.4395.

In a similar manner other dialkyl monochloromethanephosphonates were prepared having the properties shown in the following Table I.

Table I Monochloromethanephosphonates Di-iso- Dl(2- Dipropyl Dlbutyl Diamyl Dihexyl octyl Ethyl; Dinonyl Didecyl Boiling Point:

Press.,mm 1.0 1.0. Refractive Index N p 3 1.4570. 1.4545 Acidity, m1. Mo N NaOH/ 0.03-- 0.01 .06 0.03 0.03. Ool0r Same.-. Same.-- Same Same Same Same Same.

Sp. G 1.0782 1.0373--. 1.0193--. 0.9891"... 0.9949--. 0.9736 0.9698. Found:

Percent P 12.7 11.3..-" 10.4-.. 8.7 8.8 8.0 7.5.

Percent 01... 14 8- 13.0"... 11.9 10.0 10.1... 9.2 8.5. Calcd:

Percent P 8.7 8.7 8.1 7.5.

Percent 01 10.0 10.0-. 9.2 8.5. Thermal Stability, percent decomposed.. 3.55"-" Hydrolytic Stability, percent decomp 0.12 Volatility, percent Wt. loss 0.1 Freezing Point, G Flash point:

O en Oger 250 same Closed Viscosity, cp. 30 C Surface Tension, Dynes/em. at 30 0...-

1 Viscous liquid at and heating at.145-150." C. for 24 hours.

The data on thermal stability in the above Table I were determined by placing a weighed amount of the ester in a B-necked flask equipped with stirrer and thermometer The increased acidity as determined by titration with l N caustic sodawas used to calculate the percentage of ester decomposition.

Hydrolytic stability was determined by refluxing a mixture of 100 ml. water and grams of the ester for a period 7 of 24 hours, cooling and titrating the aqueous phase, with 1/3 N caustic soda to determine developedacidity which was then calculated as percentage of ester decomposition. Volatility was determined by heating the ester in a flask with stirring at l45150 C. for 24 hours and determining the percentage weight loss.

The above ester compounds are. soluble. in methanol, ethanol, acetone, methyl acetate, benzene, hexane and carbon tetrachloride, but insoluble in water.

All of the above described esters have been found to be excellent low temperature plasticizers for vinylite resin films and impart excellent flame-resistant character to the vinylite resin films.

The propyl to'hexyl species of the above esterslhave Table I-A Viscosity, centipoises Viscosity Compound Index Dtpropyl ester 4.1 1. 6 Dlbutyl este 4. 65 1. 8 Di(2Et-hexyl) est 7 9. 85 2. 7 Diisooetyl ester 11.1 3. 4

V The viscosity indexes shown were calculated from the above viscosity data by the method described in ASTM Standard QD 151, AM S3, 1953-55, p. 88.

Plasticized resin or plastic'products may be produced by intimately mixing with the desired resin or plastic material a plasticizing proportion of the monochloromethanephosphonate, with or without the aid of suitable St. Venant (British Air Ministry Specifications) solventsJ In general, it has been found that desirable pla'sticizing efiects may be. obtained where the proportion of the plasticizing ester is within the range of 20 to 40 parts by weight per 100 parts of the resin or plastic to and the plasticizer.

Cloudiness in the film is an indication of incompatibility and is an undesirable characteristic though it does not necessarily mean that no plasticizing effect is present.

Exudate is a term used to designate the presence of exuded plasticizer on the surface of the plasticized resin or plastic film. Its presence or absence is determined by rubbing a cigarette paper over the surface of the film (previously dried for 4 hours at 80 C.) and noting whether or not the paper shows any absorption of the plasticizer. The test is a measure of compatibility not observable by the visual clarity of film test. The examples reported in Table H show that in all cases the new plasticizing agents are compatible with resins or plastics tested.

Flammability. of the plasticized resin or. plastic .films was determined by holding a flame at the bottom of a vertically-hung film (approx. 0.03 inch thick)for several ature plasticizers when compared 'to the plasticizing.

be plasticized. Such plasticized products are suitable f for use as molding compounds or in the form of films or coatings in a variety of commercial applications.

Evaluation of the new monochloromethanephosphonates. as plasticizers was made by dissolving the resin or plastic andplasticizer compound in-a suitable mutual solvent, casting films therefrom of uniform thickness and methanephosphonates; The films were then tested to evaluate the plasticizerand determine thecharacteristics of the plasticized resin products Some typical examples are shown in Table II.

Film clarity is determined by visual observation, and W is a measure of the compatibility of the resin or plastic seconds, then removing'the flame. If the film continued to burn, it was designated as flammable? If the flame is immediately extinguished, it is designated self-eittin: guishing. If the film chars or melts without flaming except during the application of the flame source, it is said to be nonflammable. From the examples shown in Table II, the new esters are excellent plasticizers for vinylite, cellulose acetate, nitrocellulose and'ethyl cellulose resins or plastics, but the additional advantage of increased flame-resistance is of considerable importance only inconnection with the vinylite and cellulose acetate resins or plastics.

Moduli of Rigidity as reported for some of the plustic films in Table II represent a quantitative measure of the flexibility of the films at a temperature of about minus 50 C. The lower the figure reported, the more" desirable and more flexible is the film at the low temperature. Thus, for example, the preferred plasticizers for Vinylite film are within the group ranging from dibutyl to dioctyl monochloromethanephosphonates. However, all of the ester compounds ranging from the dipropyl to didecyl esters are highly satisfactory low temperetfect of tricresyl phosphate, a well known plasticizer of the prior art. The Modulus of Rigidity test was made using a modification of the procedure and apparatus described in the paper Measurement of Flexibility of ratus is a calibrated rotation element attached to the From'the torque measurement torque calibrated wire. when the film strip is twisted through a anglethe modulus of rigidity is calculatedfrom the formula. by

where G is the modulus of rigidity indynes/cmfi; where T=applied torque in dynes/crn.; L=length of film strip,

cm.; C=width, cm.; d=thickness, cm.; b=angle of twist, radians; and a=constant 0.313 for flatstrip shape.

The testing apparatus is placed in a vessel maintained.

at the desired temperature while conducting the tests.

"In the present examples, the temperature was held at The film thickness was 0.035 7 minus 50- C.i1. inchi0.0003 and the width 0.25 inchi0.04. Qualitative low temperature flexibility tests having good correlation with the above tests were made on films of 'Table II by immersing film specimens ina vessel at'minus 1505C. and bending the films with tongs a number of times. All of the plastic film' of Table II tested showed good to excellent flexibility at minus 50 C.

General plasticity of the plasticized films at room tem-' Ratio of Moduli Resin Plasticizer Plastic or Solvent Film clarity Exudate Flexibility Flamma-t of Resin/Plasat -50 0. bility rigidity tlcizer Dlpropyl monochloro- 100/20 Methylethyl- Clear None--.. Excellent" Self-extlng 6.5)(10 methanephosphonate. ketone. 100/30 dn dn dn fin rln do 100/40 do do do do do Dlbutyl monochloro- 100/20 do do do do 6.7X10

methanephosphonate. 0 100/30 dn do do do dn do 100/40 do dn dn do do Vinyllte (copolymer of g 'gtgg ggii g f gj 100/20 vinyl chloride home P and 5% vinyl acetate). p do do 0.- 100/40 ...--d0 Dllsooctyl monochloro- 100/20 do do do -do .do 6.5)(

methanephosphonate. Dinonyl monochloro- 100/20 .-.do do do.. Good .do 7.7)(10 methanephosphonate. Dldecyl monoehlorodo -.do 6.7)(10' methanephosphonate. Trlcresyl phosphate Poor. do 9. 3X10 Dipropyl monochloro- .--..do

methanephosphonate. do Excellent" do --do do Dlhutyl monochloro- Firm-"m n methanephosphonate. do

o Diamyl monochlorometh- Cellulose Acetate anephosphonate.

Dihexyl monochloro- Excellent .do..-.

methanephosphonate. Diisooctyl monochloro- 100/20 do S1,c1oudy -do-- ,.do

methanephosphonate. D1 (Qethyl-hexyl) mono 100/20 do Cl0udy ..-do Flamchloromethanephosphoruable. na e. Tricresyl phosphate 100/20 do White ppt -do.. Poor Non-grub ma e. Dipropyl monochloro- 100/20 Mixture of Cl ar do Flammethanephosphonate. methylethyl mable.

ketone, butyl acetate, toluene, and ethanol. 100/30 d 100/40 100/20 Nitrocellulose 100/30 0 100/40 Dlisoootyl m nochlo 100/20 methanephosphonate. D1 (Q-ethyl-hexyl) mono- 100/20 chloromethanephosphonate. Tricresyl Phosphate 100/20 Poor do "Dipropyl monochloro- 100/20 .do .o

methanephosphonate.

do 100/30 Excel1ent do d0 100/40 Dibutyl monoehloro- 100/20 methanephosphonate. Ethyl cellulose do 100/30 0 100/40 Diisooctyl monochloro- 100/20 methanephosphonate.

Dl (2-ethyl-hexyl) mono- 100/20 chloromethanephosphonate.

Tricresyl phosphate 100/20 Poor do Norm-The dashes" indicate instances where no determination was made.

perature were determined organoleptically by at least three observers and all of the films plasticized with the new esters were rated as having good to excellent plasticity.

It will be noted from the foregoing tables and discussion that all of the compounds having from 3 to 10 carbon atoms in the hydrocarbon radical have considerable value for the purposes disclosed. The compounds with 4 to 8 carbon atoms in the hydrocarbon radical, however, have improved values for some of the purposes described.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

We claim:

class consisting of vinyl chloride-vinyl acetate copolymer, cellulose acetate, nitrocellulose and ethyl cellulose, and a plasticizing proportion of a dialkyl monochloromethanephosphonate in which the alkyl radicals contain from 3 to 10 carbon atoms.

2. A vinyl chloride-vinyl acetate copolymer having therein a plasticizer comprising from 20 to 40 parts by weight per 100 parts of copolymer of a dialkyl monochloromethanephosphonate in which the alkyl groups each contain 3 to 10 carbon atoms.

3. A vinyl chloride-vinyl acetate copolymer having therein a plasticizer comprising from 20 to 40 parts by weight per 100 parts of di(2-ethy1hexyl) monochlorm methanephosphonate.

4. A cellulose acetate plastic having therein a plasticizer comprising from 20 to 40 parts by weight per 1. A plasticized material comprising a plastic of the parts of plastic of a dialkyl monochloromethane- 7 7" r 8 phosphonate in which the alkyl groups each contain 3 to r j 7 References Cited in the file of this patent atpms' V UNITED STATES PATENTS ii-A plastic as set fortflin clainT 4 in Tvhich I JhOS I H phonate is-diprop'yl monochlnromethanephdsphonate. ,573,568 Harman'etsal; Oct. 30, 1951 6; A plastic as set forth in claim 4 in which the phos- 5 0 Y et a1 y 1955 7 phonate is dibutyl monochloromethanephosphonate. s is V U T .7 T. H Q 7 V v V V V V FOREIGN PATENTS V 603,840 France Jan. 13, 1926 

1. A PLASTICIZED MATERIAL COMPRISING A PLASTIC OF THE CLASS CONSISTING OF VINYL CHLORIDE-VINYL ACETATE COPOLYMER CELLULOSE ACETATE, NITROCELLULOSE AND ETHYL CELLULOSE, AND A PLASTICIZING PROPORTION OF A DIALKYL MONOCHLOROMETHANEPHOSPHONATE IN WHICH THE ALKYL RADICALS CONTAIN FROM 3 TO 10 CARBON ATOMS. 